content: /*
   * Copyright 2016-present David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package hu.akarnokd.rxjava3.operators;
  
  import java.util.Objects;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.functions.*;
  
  /**
   * Additional operators in the form of {@link MaybeTransformer},
   * use {@link Maybe#compose(MaybeTransformer)}
   * to apply the operators to an existing sequence.
   * 
   * @see Maybes
   * @since 0.20.2
   */
  public final class MaybeTransformers {
  
      /** Utility class. */
      private MaybeTransformers() {
          throw new IllegalStateException("No instances!");
      }
  
      /**
       * Maps the terminal signals of the upstream into {@link MaybeSource}s and
       * subscribes to it, relaying its terminal events to the downstream.
       * @param <T> the success type of the upstream
       * @param <R> the success type of the resulting Maybe
       * @param onSuccessHandler a function called with the upstream success value and should
       * return a MaybeSource to continue with.
       * @param onCompleteHandler called when the upstream completes normally and should return
       * the MaybeSource to continue with.
       * @param onErrorHandler called when the upstream fails and should return the
       * MaybeSource for the given Throwable instance to continue with.
       * @return the new MaybeTransformer instance
       * @since 0.20.2
       */
      public static <T, R> MaybeTransformer<T, R> flatMap(
              Function<? super T, ? extends MaybeSource<? extends R>> onSuccessHandler,
              Function<? super Throwable, ? extends MaybeSource<? extends R>> onErrorHandler,
                      Supplier<? extends MaybeSource<? extends R>> onCompleteHandler) {
          Objects.requireNonNull(onSuccessHandler, "onSuccessHandler is null");
          Objects.requireNonNull(onErrorHandler, "onErrorHandler is null");
          Objects.requireNonNull(onCompleteHandler, "onCompleteHandler is null");
          return new MaybeFlatMapSignalMaybe<>(null, onSuccessHandler, onErrorHandler, onCompleteHandler);
      }
  }
  